commit f59ca05871a055a73f8e626f2d868f0da248e22c
author Shan Hai <haishan.bai@gmail.com> Thu Sep 01 11:32:03 2011 +0800
committer Ingo Molnar <mingo@elte.hu> Tue Sep 13 11:12:22 2011 +0200
tree dd077b2cbbf92f9dbda925d8bff9e567f5a56b3f
parent 3b8f40481513a7b6123def5a02db4cff96ae2198

locking, lib/atomic64: Annotate atomic64_lock::lock as raw

The spinlock protected atomic64 operations must be irq safe as they
are used in hard interrupt context and cannot be preempted on -rt:

 NIP [c068b218] rt_spin_lock_slowlock+0x78/0x3a8
  LR [c068b1e0] rt_spin_lock_slowlock+0x40/0x3a8
 Call Trace:
  [eb459b90] [c068b1e0] rt_spin_lock_slowlock+0x40/0x3a8 (unreliable)
  [eb459c20] [c068bdb0] rt_spin_lock+0x40/0x98
  [eb459c40] [c03d2a14] atomic64_read+0x48/0x84
  [eb459c60] [c001aaf4] perf_event_interrupt+0xec/0x28c
  [eb459d10] [c0010138] performance_monitor_exception+0x7c/0x150
  [eb459d30] [c0014170] ret_from_except_full+0x0/0x4c

So annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Shan Hai <haishan.bai@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

lib/atomic64.c

diff --git a/lib/atomic64.c b/lib/atomic64.c
index e12ae0d..82b3313 100644
--- a/lib/atomic64.c
+++ b/lib/atomic64.c
@@ -29,7 +29,7 @@
  * Ensure each lock is in a separate cacheline.
  */
 static union {
-	spinlock_t lock;
+	raw_spinlock_t lock;
 	char pad[L1_CACHE_BYTES];
 } atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp;
 
@@ -48,9 +48,9 @@
 	spinlock_t *lock = lock_addr(v);
 	long long val;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	val = v->counter;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
 EXPORT_SYMBOL(atomic64_read);
@@ -60,9 +60,9 @@
 	unsigned long flags;
 	spinlock_t *lock = lock_addr(v);
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	v->counter = i;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 }
 EXPORT_SYMBOL(atomic64_set);
 
@@ -71,9 +71,9 @@
 	unsigned long flags;
 	spinlock_t *lock = lock_addr(v);
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	v->counter += a;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 }
 EXPORT_SYMBOL(atomic64_add);
 
@@ -83,9 +83,9 @@
 	spinlock_t *lock = lock_addr(v);
 	long long val;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	val = v->counter += a;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
 EXPORT_SYMBOL(atomic64_add_return);
@@ -95,9 +95,9 @@
 	unsigned long flags;
 	spinlock_t *lock = lock_addr(v);
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	v->counter -= a;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 }
 EXPORT_SYMBOL(atomic64_sub);
 
@@ -107,9 +107,9 @@
 	spinlock_t *lock = lock_addr(v);
 	long long val;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	val = v->counter -= a;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
 EXPORT_SYMBOL(atomic64_sub_return);
@@ -120,11 +120,11 @@
 	spinlock_t *lock = lock_addr(v);
 	long long val;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	val = v->counter - 1;
 	if (val >= 0)
 		v->counter = val;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
 EXPORT_SYMBOL(atomic64_dec_if_positive);
@@ -135,11 +135,11 @@
 	spinlock_t *lock = lock_addr(v);
 	long long val;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	val = v->counter;
 	if (val == o)
 		v->counter = n;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
 EXPORT_SYMBOL(atomic64_cmpxchg);
@@ -150,10 +150,10 @@
 	spinlock_t *lock = lock_addr(v);
 	long long val;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	val = v->counter;
 	v->counter = new;
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
 EXPORT_SYMBOL(atomic64_xchg);
@@ -164,12 +164,12 @@
 	spinlock_t *lock = lock_addr(v);
 	int ret = 0;
 
-	spin_lock_irqsave(lock, flags);
+	raw_spin_lock_irqsave(lock, flags);
 	if (v->counter != u) {
 		v->counter += a;
 		ret = 1;
 	}
-	spin_unlock_irqrestore(lock, flags);
+	raw_spin_unlock_irqrestore(lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(atomic64_add_unless);
@@ -179,7 +179,7 @@
 	int i;
 
 	for (i = 0; i < NR_LOCKS; ++i)
-		spin_lock_init(&atomic64_lock[i].lock);
+		raw_spin_lock_init(&atomic64_lock[i].lock);
 	return 0;
 }